Why do I overlook the obvious?

20 November 2013


Saggital transection through the human brain



Why does my brain sometimes overlook the obvious? Today, in the garden, I was multi-tasking a bit too much and this involved my putting my glasses on top of my head. They fell off of course, I looked everywhere, but couldn't see them even though they are bright purple. I found them close by where I had surely looked a minute before. Why didn't I see them the first time my eyes passed over that spot?


So why could Juliet not find her glasses? She swears she can still see without them, so why did she overlook finding them? Professor Nilli Lavie from University College London.

Nilli Lavie - This is because people experience the phenomenon that we term load induced blindness, when the brain is overloaded. Multi-tasking will often overload the brain and this will result in some parts of the brain not being able to respond to the environment temporarily.

Hannah - So Juliet overloaded her thoughts whilst looking for her glasses. But what was going on in her brain to mean she couldn't see the thing that she was specifically looking for?

Nilli Lavie - If a certain information is there it's not enough that the eye can see it. It's also important that the information is registered in the visual cortex. However, in conditions of overload, the visual cortex will temporarily not be able to respond to the visual environment and this will result in the experience of blindness. Of course this is not real blindness, but because the visual cortex does not register the pair of glasses in the example, we experience as if cortical form of blindness.

Hannah -So information overload, leading to visual cortex blindness. Thanks Juliet for getting in touch with that question and Nilli for the answer


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